Unsaturated fatty acids are inhibitors of bacterial conjugation

This report describes a high-throughput assay to identify substances that reduce the frequency of conjugation in Gram-negative bacteria. Bacterial conjugation is largely responsible for the spread of multiple antibiotic resistances in human pathogens. Conjugation inhibitors may provide a means to control the spread of antibiotic resistance. An automated conjugation assay was developed that used plasmid R388 and a laboratory strain of Escherichia coli as a model system, and bioluminescence as a reporter for conjugation activity. Frequencies of conjugation could be measured continuously in real time by the amount of light produced, and thus the effects of inhibitory compounds could be determined quantitatively. A control assay, run in parallel, allowed elimination of compounds affecting cell growth, plasmid stability or gene expression. The automated conjugation assay was used to screen a database of more than 12 000 microbial extracts known to contain a wide variety of bioactive compounds (the NatChem library). The initial hit rate was 1·4 %. From these, 48 extracts containing active compounds and representing a variety of organisms and extraction conditions were subjected to fractionation (24 fractions per extract). The 52 most active fractions were subjected to a secondary analysis to determine the range of plasmid inhibition. Plasmids R388, R1 and RP4 were used as representatives of a variety of plasmid transfer systems. Only one fraction (of complex composition) affected transfer of all three plasmids, while four other fractions were active against two of them. Two separate compounds were identified from these fractions: linoleic acid and dehydrocrepenynic acid. Downstream analysis showed that the chemical class of unsaturated fatty acids act as true inhibitors of conjugation

677. Systematic Review of the Early Use Experince of Cefiderocol in Real World Practice

Abstract Background Gram-negative bacteria (GNB) with resistance to carbapenems is a growing global public health concern. The World Health Organisation have listed three priority GNB pathogens for the development of novel antimicrobial agents; Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacterales. The purpose of this systematic review (SR) was to report evidence on the use of cefiderocol (FDC), a siderophore cephalosporin, for patients with GNB infections in compassionate use or expanded access settings. Methods Searches were undertaken to identify relevant evidence up to December 2021. Two independent reviewers screened the records retrieved for relevance to the SR with disagreements adjudicated by a third reviewer. Patients receiving FDC in a compassionate use, expanded access setting or those with limited treatment options for the treatment of GNB infection were eligible. Eligible case reports and case series were assessed for quality using predefined tools and data were extracted (by a single reviewer with data checking performed by a second reviewer), tabulated and summarised. Results Forty-four studies (n=150 patients) were identified reporting the use of FDC; 3 case series studies and 41 case reports. The most commonly reported pathogens were P. aeruginosa (41.3%), A. baumannii (36.0%) and A. xylosoxidans (14.3%). The diagnoses varied widely across the included patients. All patients were administered FDC at a dose between 750 mg and 2 g per day on various schedules, adjusted for renal function for between one and six weeks. Clinical cure was reported in 137 patients using author-specified definitions with 74 patients (54.0%) reporting clinical cure and 18 (13.1%) reporting failure. Microbiological eradication was reported in 78 patients of whom 56 (71.8%) reported success, while 22 (28.2%) reported failure. For mortality (n=123) 80 patients (65.0%) remained alive at the end of treatment, while 43 (35.0%) died. Adverse event (AE) data was reported for 53 patients of whom 13 (24.5%) reported AEs, while 40 (75.5%) did not. See Table 1.0. Conclusion FDC is a promising therapy for patients with GNB infections with limited treatment options. Real world practice shows a high microbiological eradication rate and a small number of AEs. Disclosures Carlo Tascini, n/a, Shionogi: Grant/Research Support Aurelien Dinh, Professor of Infectious Disease, Shionogi: Advisor/Consultant|Shionogi: Board Member Christopher M. Longshaw, PhD, Shionogi: Employee Anita C. Fitzgerald, MPH, Shionogi: Shionogi commissioned York Health Economics Consortium of which I am an associate, to conduct the systematic review we are submitting to IDWeek Hannah Wood, BA MA, Shionogi: Shionogi commissioned York Health Economics Consortium of which I am an employee, to conduct the systematic review we are submitting to IDWeek Jacoby Vivien M. Patterson, MA Cantab, MB BChir, FFPH MD, Shionogi: Shionogi commissioned York Health Economics Consortium of which I am an associate, to conduct the systematic review we are submitting to IDW Deborah Watkins, MSc, Shionogi: Shionogi commissioned York Health Economics Consortium of which I am an employee, to conduct the systematic review we are submitting to IDWeek Katy Wilson, LLM, Shionogi: Shionogi commissioned York Health Economics Consortium of which I am an employee to conduct the systematic review we are submitting to IDWeek Karan Gill, Master of Science, Shionogi: Employee

The ClosER study: results from a three-year pan-European longitudinal surveillance of antibiotic resistance among prevalent Clostridium difficile ribotypes, 2011–2014

Objectives: Until the introduction of fidaxomicin, antimicrobial treatment for Clostridium difficile infection (CDI) was limited to metronidazole and vancomycin. The changing epidemiology of CDI and the emergence of epidemic C. difficile PCR ribotype 027 necessitate continued surveillance to identify shifts in antibiotic susceptibility. ClosER, currently the largest pan-European epidemiological study of C. difficile ribotype distribution and antibiotic susceptibility, aimed to undertake antimicrobial resistance surveillance pre- and post-introduction of fidaxomicin. Methods: Between July 2011 and July 2014, 39 sites across 22 European countries submitted 2830 C. difficile isolates for ribotyping, toxin testing and susceptibility testing to metronidazole, vancomycin, fidaxomicin, rifampicin, moxifloxacin, clindamycin, imipenem, chloramphenicol and tigecycline. Results: Ribotypes 027, 014, 001, 078, 020, 002, 126, 015 and 005 were most frequently isolated, and emergent ribotypes 198 and 356 were identified in Hungary and Italy, respectively. All isolates were susceptible to fidaxomicin, with scarce resistance to metronidazole (0.2%, 6/2694), vancomycin (0.1%, 2/2694) and tigecycline (0%). Rifampicin, moxifloxacin and clindamycin resistance was evident in multiple ribotypes. Lack of ribotype diversity correlated with greater antimicrobial resistance. Epidemic ribotypes (027/001) were associated with multiple antimicrobial resistance, and ribotypes 017, 018 and 356 with high-level resistance. Additional factors may also influence local ribotype prevalence. Conclusions: Fidaxomicin susceptibility was retained post-introduction, and resistance to metronidazole and vancomycin was rare. Continued surveillance is needed, with more accurate classification and clarification of ribotype subtypes to further understand their role in the spread of resistance. Other factors may also influence changes in prevalence of C. difficile ribotypes with reduced antibiotic susceptibility

Genotypic and phenotypic variation among Staphylococcus saprophyticus from human and animal isolates

<p>Abstract</p> <p>Background</p> <p>The main aim of this study was to examine the genotypic and phenotypic diversity of <it>Staphylococcus saprophyticus </it>isolates from human and animal origin.</p> <p>Findings</p> <p>In total, 236 clinical isolates and 15 animal isolates of <it>S. saprophyticus </it>were characterized in respect of the occurrence of 9 potential virulence genes and four surface properties. All strains were PCR positive for the regulatory genes <it>agr</it>, <it>sar</it>>it>A and <it>rot </it>as well as for the surface proteins UafA and Aas. Nearly 90% of the clinical isolates were found to possess the gene for the surface-associated lipase Ssp and 10% for the collagen binding MSCRAMM SdrI. All animal isolates were negative for<it>sdrI</it>. Lipolytic activity could be detected in 66% of the clinical and 46% of the animal isolates. Adherence to collagen type I was shown of 20% of the clinical strains and 6% of the strains of animal origin. Most <it>S. saprophyticus </it>strains showed hydrophobic properties and only few could agglutinate sheep erythrocytes.</p> <p>Conclusions</p> <p>We described a broad analysis of animal and human <it>S. saprophyticus </it>isolates regarding virulence genes and phenotypic properties such as lipase activity, hydrophobicity, and adherence. While <it>S. saprophyticus </it>strains from animal sources have prerequisites for colonization of the urinary tract like the D-serine-deaminase, out findings suggested that they need to acquire new genes e.g. MSCRAMMS for adherence like sdrI and to modulate their existing properties e.g. increasing the lipase activity or reducing hydrophobicity. These apparently important new genes or properties for virulence have to be further analyzed.</p

A framework for teaching epistemic insight in schools

This paper gives the rationale and a draft outline for a framework for education to teach epistemic insight into schools in England. The motivation to research and propose a strategy to teach and assess epistemic insight followed research that investigated how students and teachers in primary and secondary schools respond to big questions about the nature of reality and human personhood. The research revealed that there are pressures in schools that dampen students’ expressed curiosity in these types of questions and limit their developing epistemic insight into how science, religion and the wider humanities relate. These findings prompted the construction of a framework for education for students aged 5–16 designed to encourage students’ expressed interest in big questions and develop their understanding of the ways that science interacts with other ways of knowing. The centrepiece of the framework is a sequence of learning objectives for epistemic insight, organised into three categories. The categories are, firstly, the nature of science in real world contexts and multidisciplinary arenas; secondly, ways of knowing and how they interact; and thirdly, the relationships between science and religion. Our current version of the Framework is constructed to respond to the way that teaching is organised in England. The key principles and many of the activities could be adopted and tailored to work in many other countries

Parasites, pathogens and commensals in the “low-impact” non-native amphipod host Gammarus roeselii

Background: Whilst vastly understudied, pathogens of non-native species (NNS) are increasingly recognised as important threats to native wildlife. This study builds upon recent recommendations for improved screening for pathogens in NNS by focusing on populations of Gammarus roeselii in Chojna, north-western Poland. At this location, and in other parts of continental Europe, G. roeselii is considered a well-established and relatively ‘low-impact’ invader, with little understanding about its underlying pathogen profile and even less on potential spill-over of these pathogens to native species. Results: Using a combination of histological, ultrastructural and phylogenetic approaches, we define a pathogen profile for non-native populations of G. roeselii in Poland. This profile comprised acanthocephalans (Polymorphus minutus Goese, 1782 and Pomphorhynchus sp.), digenean trematodes, commensal rotifers, commensal and parasitic ciliated protists, gregarines, microsporidia, a putative rickettsia-like organism, filamentous bacteria and two viral pathogens, the majority of which are previously unknown to science. To demonstrate potential for such pathogenic risks to be characterised from a taxonomic perspective, one of the pathogens, a novel microsporidian, is described based upon its pathology, developmental cycle and SSU rRNA gene phylogeny. The novel microsporidian Cucumispora roeselii n. sp. displayed closest morphological and phylogenetic similarity to two previously described taxa, Cucumispora dikerogammari Ovcharenko, 2010 and Cucumispora ornata Bojko, 2015. Conclusions: In addition to our discovery extending the host range for the genus Cucumispora Ovcharenko, 2010 outside of the amphipod host genus Dikerogammarus Stebbing, we reveal significant potential for the co-transfer of (previously unknown) pathogens alongside this host when invading novel locations. This study highlights the importance of pre-invasion screening of low-impact NNS and, provides a means to document and potentially mitigate the additional risks posed by previously unknown pathogens